Various types of medico-surgical tubes employing means for administering medication to a selected site in a body are known in the art. For instance, such tubes include catheters and endotracheal tubes.
A catheter having means for administering liquid medicaments or other preparations is disclosed in U.S. Pat. No. 3,593,713 ("Bogoff"). Bogoff discloses a catheter having a tube surrounded by a tubular jacket which includes a perforated or foraminous area through which a fluid, such as a liquid medicament including antibiotics and anesthetic, can be dispersed within and along the walls of a body orifice, cavity or opening in which the catheter is inserted at the time.
U.S. Pat. No. 3,981,299 ("Murray") discloses a urethral catheter which includes a thin outer membrane provided with a plurality of pores or openings for permitting injections of antibiotics, medication, anesthetics or simple irrigation of the urethral passage.
U.S. Pat. No. 4,186,745 ("Lewis") discloses a catheter having conducting passages within a micropore structure for controlled release of substances such as distilled water, antiseptics, antibiotics, enzymes and other substances.
An endotracheal tube having means for introducing medicinal fluids into the trachea is disclosed in U.S. Pat. No. 4,305,392 ("Chester"). Chester discloses an endotracheal tube having a cylindrical wall, a main lumen defined by an inner surface of the wall, a first secondary lumen within the wall for inflation of a balloon cuff and a second secondary lumen within the wall in fluid communication with a suction chamber having four ports equally spaced about the periphery of the chamber. The ports of Chester's tube are ovoid in shape and are used for introducing anesthesia or irrigation fluid into the trachea or for providing suction without grabbing or invaginating the tracheal mucosa such as for removal of blood clots and other secretions.
U.S. Pat. No. 4,327,721 ("Goldin") discloses a medical device such as an endotracheal tube provided with an annular chamber surrounding an insertion tube wall. A plurality of fenestrations or openings are provided in the chamber and are appropriately shaped so as to atomize a fluid being delivered under pressure thereto through a secondary lumen. The openings in Goldin's tube are used for administering topically active medications, such as local anesthesia, to the tracheal wall and for aspirating any mucous which accumulates above an inflated cuff of the tube.
U.S. Pat. Nos. 4,549,879; 4,671,796; and 4,701,166 ("Groshong") disclose a catheter which includes a closed end and a fluid opening formed by a single linearly extending slit through the tubing wall. The slit forms a two-way valve which remains closed under normal physiologic pressures but is intended to open upon application of predetermined pressure differentials to allow fluid to flow out or be drawn into the catheter. The slit is made by providing a cut through the catheter wall in a direction parallel to the axis of the catheter. The differential pressure required to open the slit is adjusted by changing the slit length.
U.S. Pat. No. 4,693,242 ("Burns") discloses a flexible, non-collapsible conduit system separable but positioned around a standard cuffed, endotracheal tube to allow for direct topical application of medicinal substances to tissues of the larynx and trachea. The tube of Burns includes a secondary lumen in the tube wall which opens into a non-collapsible conduit ring fixed around a proximal end of the inflatable cuff and outer perforations in the conduit ring leak topical anesthetic or other medicinal fluid to the adjacent upper tracheolaryngeal areas. Additional conduits having outer perforations or openings are connected to the conduit for leaking topical anesthetic or other medicinal fluid to adjacent lower tracheal or bronchial area. The perforations of Burns are elliptical in shape as viewed along the outer periphery of the conduits and are formed by tapered openings which become wider in a direction towards the outer periphery of the conduits, the conduit system maintaining fluid communication regardless of the manipulation of the tube or cuff.
In general, an endotracheal tube is a plastic or rubber, most commonly PVC, tube used for securing the airway of critically ill or anesthetized patients. Such a tube is necessary in order to perform mechanical positive pressure ventilation of the lungs and to prevent the possibility of aspiration or airway obstruction.
The larynx and trachea, through which this tube must pass, are amongst the most sensitive areas of the body. The presence of a tube in these structures invokes powerful reflexes of pain, coughing, gagging, retching and vomiting. It is advantageous to administer a local anesthetic containing solution to the larynx and trachea on initial placement of the tube and subsequently as required while the tube is still in place. This prevents the pain, discomfort and potentially dangerous fits of coughing that might be produced by the presence of the tube in the larynx and trachea. Removing the tube to administer local anesthetic is time consuming, difficult and occasionally dangerous. An endotracheal tube is disclosed in commonly owned U.S. Pat. No. 4,977,894, issued on Dec. 18, 1990, which matured from Ser. No. 07/334,435 filed on Apr. 7, 1989, a continuation of Ser. No. 07/031,877 filed on Mar. 30, 1987, the disclosure of which is hereby incorporated by reference. The endotracheal tube includes means for administering local anesthetic to the sensitive laryngo-tracheal area through the wall of the endotracheal tube. In particular, several small openings in fluid communication with an injection lumen in the wall of the tube are provided on the anterior aspect of the distal 11 cm of the tube corresponding to the anatomical position of the epiglottis, larynx and trachea.